CFD Simulation of Propane Thermal Cracking Furnace and Reactor: A Case Study

Abstract

Abstract In the present work, a different new arrangement of side-wall burners of an industrial furnace with varying fuel flow rate was studied by three-dimensional CFD simulation. Tube skin temperature and heat flux profiles were obtained by solving mass, momentum and energy equations of the furnace by Ansys Fluent software. A reasonable fuel flow rate ($$\dot m$$=0.0695 kg/s) was assigned and effect of different ratio of this rate (0.25$$\dot m$$, 0.5$$\dot m$$, 2$$\dot m$$, 4$$\dot m$$) was investigated on reactor tube skin temperature profiles. Heat and temperature non-uniform distribution was observed by proposed arrangement. It was found that proper range for fuel rate was 0.5$$\dot m$$ to 2$$\dot m$$. Temperature profiles were used in one dimensional plug flow reactor model equations to consider fuel rate variations on reactor performance. By the proposed burner arrangement, Propane conversion and Ethylene yield obtained 6.25 % and 7.2 % more than the base case. Furthermore coil outlet temperature (COT) decreased about 7 °C. Also, feed flowrate was taken as an effective parameter on reactor process under no coke formation condition. Results showed that by increasing fuel rate, outlet Propylene yield decreased, while, process gas temperature, pressure drop, process severity (propane conversion) and Ethylene yield increased along the reactor tube i. e. for 0.5$$\dot m$$ to 2$$\dot m$$ at 0.8 kg/s reactor flowrate, Propylene yield decreased 15.95 % and reached to zero, whereas Ethylene yield increased 16.5 %. Also, in any fuel rate, by increasing reactor feed flowrate, even though the reactor coil outlet temperature decreased, the desired product yields increased. At 0.95 kg/s reactor flowrate, maximum Ethylene yield was obtained about 45.5 % at 1$$\dot m$$ kg/s; while, Propylene yield production at 0.5$$\dot m$$ kg/s fuel rate was 22.41 %.